Extended periodic table
The extended periodic table was presented by Glenn T. Seaborg in 1969. On the whole, it corresponds to the previous period system in function and structure, but this adds to the Elements with atomic numbers greater than 118 and engages more sub-groups. Since these additional elements have not yet been created, they have for the time being systematic element name. Moreover, it is strictly sorted by assignment of the electron orbitals, which is why, for example, helium is ( He) on the left, to the right of hydrogen ( H) and not quite right about neon.
Nuclear physics
From one generation to the addition considered in this schema elements with atomic numbers beyond 118 is not known. However, their manufacturability by nuclear fusion is highly likely based on theoretical considerations. It is expected that these elements decay with half-lives less than a second. Some elements are probably relatively long-lived relative to their neighbors, because they are on islands of stability. In the real sense " stable " super-heavy elements are not in the realm of what is expected.
Anomalies and peculiarities which only occur with larger atomic numbers (eg, from 300 or 500 ) can not now be reliably predicted.
Historically neutron stars with very large atoms were compared with atomic numbers in many orders of magnitude, but is now regarded as inadmissible because of the addition involved physical phenomena ( gravity, plasma formation ).
Chemistry
It is believed that the elements with atomic numbers greater than 118 follow the well-known laws of elements having a lower atomic number. However, their predicted life is too short and the producible amount too small to chemical or most of the physical properties (such as the physical state ) to observe.
It is expected that successively 5 g orbitals and to 153 6f orbitals are filled in elements 123-140, the elements 122 and 141. Glenn T. Seaborg coined the term Superactinoide for the combined group of 5 g and 6f elements. These elements are similar to the lanthanides and actinides are engaged or away from shown.
Similarly, as already in the lanthanides and actinides, the exact assignment to the Superactinoiden is not uniform in the literature.
In general, it is expected that the chemical properties of the heaviest elements due to the relativistic effect may not necessarily follow the trends of the previous periods. In this respect, the allocation to each group of the periodic table is a purely formal assignment, as long as there are no experimental data.